Occupancy sensing technologies are used to monitor the presence of human occupants in indoor and outdoor spaces. Occupancy sensing systems conserve energy by automatically turning off lighting and other electrical loads when the space is unoccupied. They may also perform a convenience function by automatically turning on lighting and other loads when an occupant enters a space.
An occupancy sensing system generally includes at least two major components: an occupancy sensor and a switching device. The sensor generally needs to be positioned in a location that is selected to have a clear view of the entire space that is to be monitored for occupants. This type of location, however, is typically not convenient for the switching device. Therefore, occupancy sensor systems generally include control wiring that runs between the occupancy sensor and the switching devices. This additional wiring tends to be expensive and time consuming to install. It may also be a source of system failures that are difficult to diagnose if the wiring is concealed in walls. Moreover, once the wiring is installed, it is difficult to reconfigure the system if there is a change in the type or location of loads that are to be controlled by the occupancy sensor.